Two birds dead.... Is the rest of my flock in danger?

Hello all,

A rooster and a hen that I had died.

1) What type of bird , age and weight (does the chicken seem or feel lighter or thinner than the others.) The rooster was a Buff Orpington, about 6-7 months old. The hen was a GLW, about 10 months old. Neither was larger or smaller than the others of the same age and gender.
2) What is the behavior, exactly. They both started out acting sad and down. Then they became kind of dizzy. At first, I thought that the rooster had fallen of the roost and had a concussion (it seemed to be getting better). Then it couldn't walk straight and then it wouldn't eat. The hen has been acting down for days now, and I had been watching her. Today, she started holding her head to one side (like she was looking at the sky, except she couldn't control it) and tipping over. She wouldn't have lasted the night. The two died at different times, the rooster about a week ago and the hen today.
3) How long has the bird been exhibiting symptoms? They acted sick for 3-4 days before days before dying.
4) Are other birds exhibiting the same symptoms? Not at the moment.
5) Is there any bleeding, injury, broken bones or other sign of trauma. No
6) What happened, if anything that you know of, that may have caused the situation. I don't know of anything...
7) What has the bird been eating and drinking, if at all. Blue seal Layer pellets and water. I'm not sure how much the two of them were eating/drinking, because they are with 14 other birds and they free-range.
8) How does the poop look? Normal? Bloody? Runny? etc. Poop looked normal.
9) What has been the treatment you have administered so far? None, I just want to know if the rest of my flock could be in danger.
10 ) What is your intent as far as treatment? For example, do you want to treat completely yourself, or do you need help in stabilizing the bird til you can get to a vet? I will not take them to a vet. I will consider treatment, but the birds are not sick at present. The ones that were sick, are dead.
11) If you have a picture of the wound or condition, please post it. It may help. I don't have one.
12) Describe the housing/bedding in use They are kept in an 8X12 shed and usually have wood shavings.

Any ideas that would lead to the identification of this issue would be greatly appreciated. I don't want to lose my whole flock!

 

Nobody has any advice? I am really worried about my birds!

 

Thanks for your reply...

I don't think that they have lice/mites, but I will check.

And they don't have worms... This is going to sound weird, but I inspect poop regularly.